We compared steroid sex hormone measurements in serum by radioimmunoassay with mass spectrometry. Four male and four female serum pools with known relative concentrations of steroid sex hormones were measured multiple times by both methods. Although absolute concentrations may differ for some hormones, radioimmunoassay and mass spectrometry can yield similar estimates of between subject differences in serum concentrations of most steroid sex hormones commonly measured in population studies. Carcinogenic human papillomaviruses (HPV) are thought to be necessary for development of cervical cancer. We published or prepared several manuscripts on human papillomavirus (HPV) and its relation to cervical dysplasia from our natural history studies in Portland, Oregon and Guanacaste, Costa Rica. We investigated whether higher viral load of oncogenic HPV types predicted higher risk of high-grade cervical lesions or cancer (CIN3+). We found no increased risk from higher viral load among infected women. We investigated the optimal performance of cervicography for detection of cervical neoplasia. Optimization of the cervigram classification improved performance over a single interpretation in this population but suggested the limits of static visual screening. We submitted a paper showing that cytology combined with testing for oncogenic HPV predicted development of high-grade cervical lesions better than cyotology or viral testing alone. We published a paper on the effects of reproductive history on risk of breast cancer in the Washington Ashkenazi Study using an extension of the kin-cohort design we developed earlier. We found that age-at-first-birth increased risk of breast cancer in non-carriers, as expected, but not in carriers. We concluded that it is not yet clear whether the recognized breast cancer risk factors operate in the same way in women who carry a mutation in the BRCA1 or BRCA2 genes. We prepare for a placebo-controlled trial of a virus-like particle and chimeric virus-like particle vaccine against HPV-16 (human papillomavirus, type 16) infection in Costa Rica; the clinical outcomes will be development of dysplasia and persistence of HPV-16 infection. The protocol has been approved by all required oversight committees. We published a paper that discusses the challenge of sorting through the individual information that will soon become available and developing effective strategies of advance molecular diagnostics. To help us identify appropriate techniques and laboratories for measuring hormones, we studied the variability and reproducibility of assay measurements. The data indicate that for at least one of the laboratories a single sample with two laboratory replicates per sample of androstanediol glucuronide, androstenedrone, DHEA, DHEA sulfate, and dihydrotestosterone yields an intraclass correlation coefficient exceeding 0.80 and can be used to discriminate reliably among men. The results for testosterone, androstanediol, androsterone, glucuronide, and androsterone sulfate do not meet this test.